We have systematically investigated the dependence of \(M\)  (the macroscopic
magnetisation of point-like samples) on \(T\)  (temperature) and \(H\)  (magnetic field),
in the range 2 \(\le T \le \)  315 K and 0.5 \(\le H \le \)  65 kOe by means of a
SQUID-magnetometer and for the above-mentioned glassy solids. In such insulating
glasses, the SQUID-characterisation is normally employed to asses the trace-like
(ppm) content of paramagnetic impurities (iron, typically) from a single \(M\)  vs.
\(1/T\)  chart at fixed \(H\) . The idea, never challenged thus far (however, see
[1]}), has been that only Fe\(^{3+}\)  is present in such systems. Then,
the best-fit to the data with the textbook form [2]} (hereafter already
extended for more than one paramagnetic species):
\(M(T,H)&=&-\chi _L~H+\sum _{s=Fe^{2+},Fe^{3+},\dots }~n_s~g_s\mu _B J_s~ {\cal B}_{J_s}(z_s), \cr z_s&\equiv &\frac{g_s\mu _BJ_sH}{k_BT}, \cr {\cal B}_J(z)&=&\frac{2J+1}{2J}\coth \Big ( \frac{2J+1}{2J} z \Big )-\frac{1}{2J}\coth \Big ( \frac{1}{2J} z \Big )\) 
